Sana’a University

Faculty of Engineering

Department of Mechanical Engineering

HVAC Course Project

HVAC System Design and Calculations

By:
Ayman Mazwed 3250/2014

Moataz Alsanabani 307/2013

Supervised By:
Dr. Eng./ Abdualjalil Alobaidi

A u g u s t – 2 0 2 0
ABSTRACT
This project is submitted for the HVAC course based on the request of the
instructor Eng. Dr/ Abudualjalil Alobidi. It is a study for a real existing
building located in Sana’a – Yemen. The building specifications and designs
from the architect and civil Engineer that designed and supervised the
construction and design of the building. The first step taken was the
thoroughly analysis of the building and its use whether it is residential or
company building. Then, determining the kind of HVAC services the
building requires (Heating only, Heating and Cooling, or Cooling only).
After that, a hand calculation for the heating and cooling loads for one space.
Then, we used HAP software to calculate the heating and cooling loads.
After that, we compared the hand calculations and the HAP report.
 TABLE OF CONTENTS

1 Building......................................................................................1

1.1 Building Layout .................................................................2

1.2 Building Location ..............................................................4
1.3 The Building Specifications ..............................................4

2 Heating and Cooling Loads Calculations...............................9

2.1 Heating Load Hand Calcuation........................................9

2.2 Cooling Load Hand Calculation .....................................11
2.3 Heating and Cooling Loads Hap Calculations ..............13
2.4 Comparsion of The Hand Calculations and The Hap
Calculations...............................................................................13

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 Chapter One

1 BUILDING

The building architecture and civil designs were obtained and analyzed. It
was informed that the building is a two floors residential building. The
building gross area is 150 m2. It contains many different purpose spaces.
Only the main spaces that will included on the study. The bathrooms and
halls will not be heated or cooled.

Figure 1. Building Model

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1.1 BUILDING LAYOUT

There are two layouts for the building floor one layout and floor two layout.
Each layout will be described and identified in the below section:

• Floor One Layout

Floor one contains six spaces and one stair way. There are two room each
4x4 m2, kitchen which is 3x2.4 m2, two bathrooms and one large hall. On
this floor, the spaces that the study will be applied on are the two rooms and
the kitchen. The bathrooms and the hall will not be included and will not be
heated nor cooled.

Figure 2. Floor One Layout

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• Floor Two Layout

Floor two contains four spaces and one stair way. There is one room large
4x10 m2, room which is 3x3.5 m2, one bathroom and one hall. On this floor,
the spaces that the study will be applied on are the two rooms. The bathroom
and the hall will not be included and will not be heated nor cooled.

Figure 3 Floor Two Layout

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1.2 BUILDING LOCATION

Th building is located on Sana’a – Sa’wan – Al aushah. As show the building

is surrounded form the north and east by two streets one is main street and
other is a miner street.

Figure 4 Building Location

1.3 THE BUILDING SPECIFICATIONS

This section will describe the building specifications the kind of walls and
materials used and the partitions layers. It will also include the ceiling used
and the doors and windows materials and dimensions. All this information
was obtained from the architect and the civil Engineer.

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  The Walls
Table 1 Walls

No. Construction Rth (m .C / W) Thickness

2 O
Layers

1 Stone 0.09524 10 cm

2 Mortar 0.3125 5 cm

Cement
3 0.2 20 cm
Block

4 Plaster 0.04166 5 cm

U = 1.28 W/ m2 CO

 The Partitions
Table 2 Partitions

No. Construction Rth (m2.CO/ W) Thickness Layers

1 Plaster 0.04166 2.5 cm

Cement
2 0.2 15 cm
Block

3 Plaster 0.04166 2.5 cm

U = 2.553 W/ m2 CO

 The Ceiling

The ceiling height is 3 m.

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 Table 3 Ceiling

Rth
No. Construction (m2.CO/ Thickness Layers
W)

1 Asphalt Mix 0.028 2 cm

2 Concrete 0.029 5 cm

3 Insulation 0.500 2 cm

Reinforced
4 0.034 6 cm
Concrete

Cement
5 0.189 18 cm
Block

6 Plaster 0.017 2 cm

U = 1.08 W/ m2 CO

 Windows

All the windows are constructed of the same materials which is aluminum –
single glass.
Table 4 Windows Coefficient

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As for the sizes of the windows there are four different sizes of windows.
The sizes of the windows are show in the below table.
Table 5 Window Types

No. Width (cm) Hight (cm) Seat (cm)

W1 150 120 100

W2 100 120 160

W3 70 70 160

W4 60 60 160

W1 150 120 100

The windows, shown in the building layouts, in the figures below.

Figure 5 Windows Maps

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  Doors

The doors only include the internal doors. The outer door of the building
will not be important for the study. The internal doors dimensions are
2x1m2 with 25mm thickness.
Table 6 Doors Coefficient

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 Chapter Two

2 HEATING AND COOLING LOADS

CALCULATIONS

This chapter will study the heating and cooling loads for all the specified
spaces and floors. The heating and cooling loads will be calculated by HAP
4.9 software. After that later in this chapter a hand calculation will be
performed as studied for only one space and a comparison between the HAP
results and the hand results.

2.1 HEATING LOAD HAND CALCUATION

The hand calculation was performed on Floor 1 Space 1.

Figure 6 F1-S1

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 Table 7 Heating Load Hand Calculations

Inside Design Condition: Ti = 23o C

Date: 2020
Outside Design Condition: To = 5o C
ᶲi = 35%
Project: Heating Load
ᶲo = 37%
Adjacent Space Temperature: Tadj=10o C

Floor 1 - Space 1 - Heating

Surface Area, m2 Uo Ti – To Qloss

Walls
A (south) 10.76 1.28 17o 234.16
B (West) 11.6 1.28 17o 252.416
C (East) 13.4 2.553 12 -----
D (North) 11.4 2.553 12 349.25
Doors 2 3.6 12 86.4
Windows
A 1.8 6.7 17o 205.02
B 1.8 6.7 17o 205.02
C 0.84 6.7 17o 95.676
Ceiling 16 1.08 0 0

Floor 16 0 0 0

Infiltration - - - 425

Miscellaneous - - - 0

Total heating load for the space Q = 1.8 kw

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2.2 COOLING LOAD HAND CALCULATION

Table 8 Cooling Loads Hand Calculations

Date: 2020 Inside Design Condition: Ti = 24o C

ᶲo = 38%
Project: Cooling Loads Outside Design Condition: To = 30o C

Room No.: F1-S1 Adjacent Space Temperature: Tadj= 28o C ᶲi = 50%

Outside mean Temperature: To,m = 28o C DR =12.9

(a) External Cooling Loads: (a) Convection due to (Tadj - Ti)

surface Area, m2 Uo, W/m2. k (Ti – To) o C Q, W

Wall A (North) 10 2.5 4 100
Wall B (East) - - - -
Glass (A) 0 0 0 0
Doors 2 3.6 4 28.8

Ceiling - - - -

Floor - - - -

Total Q = 128.8 KW

(b) Solar Effects: (i) Transmitted heat gain rates

surface Area, m2 SHG SC CLF Q,

Glass (south) 2.85 128 0.25 0.5 45.6

Glass (west) 1.8 673.1 0.25 0.72 218.1

Total Q = 263.7KW

(b) Solar Effects: (ii) Convection due to CLTD

(25.5 - Ti) = ………o C (To,m – 29.4) = ………o C

(25.5 - 24) = 1.5o C (10 – 29.4) = -5.85o C

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surface Area, m2 U CLTD CLTD corr Q,

Wall A (south) 9.15 1.28 11 6.076 71.16

Wall B (west) 10.2 1.28 6 4.665 60.91

Window (south) 2.85 6.7 8 2.2 42

Window (west) 1.8 6.7 8 3.85 46.43

Total Q = 220.5 KW

(2) Internal cooling loads:

Item Sensible Load Latent Load

Occupants 140 88

Light 384 0

Equipment - -

Hair dryer 675 120

Motor 0 0

Total 1199 208

QS – QL = 1407

(3) Infiltration

Sensible Load Latent Load

ACH = 1.5 125 25

QS – QL = 150

Q cooling = 128.8 + 263.7 + 220.5 + 1407 + 150 Q cooling = 2.17 KW

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2.3 HEATING AND COOLING LOADS HAP CALCULATIONS

The following tables were obtained from the original results table of the
HAP calculations.

Zone Sizing Data

Maximum Time Maximum Zone

Design Minimum of
Zone Name Cooling Heating Floor Zone
Airflow Airflow Peak L/(s-
Sensible (L/s) (L/s) Load Area m²)
(kW) Load (kW) (m²)
Nov
Zone 1 7.7 903 903 1500 4.5 39.2 23.03
Nov
Zone 2 2.6 452 452 1600 5.0 50.5 8.95

Space Loads and Airflows

Zone Name / Cooling Time Air Heating Floor

Mult. Sensible of Flow Load Area Space
Space Name
(kW) Load (L/s) (kW) (m²) L/(s-m²)

Zone 1
Nov
F1S1-BR 1 1.6 1500 183 1.8 16.0 11.41
Nov
F1S3-BR 1 1.1 1500 165 1.8 16.0 10.33
Nov
F1S2-Kitchen 1 4.9 1500 555 0.9 7.2 77.08
Zone 2
Nov
F2S1-Diwan 1 1.9 1600 327 3.6 40.0 8.18
Nov
F2S2-BR 1 0.7 1600 125 1.4 10.5 11.88

2.4 COMPARSION OF THE HAND CALCULATIONS AND THE

HAP CALCULATIONS

As we realized the is a slightly small difference in the HAP calculations and

hand calculations in Floor1-Space1.

Q loss, hand = 1.8 kw

Q loss, HAP = 1.8 kw

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The heating loads are the same.

Q cooling, hand = 2.17 kw

Q cooling, HAP = 1.6 kw

The cooling loads are not the same. There is a slight difference between the
cooling loads.

SHG was taken at Latitude 23

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